The present invention is directed to an apparatus and method for controlling the positioning and heat transfer from an electrical heating element to a vessel being heated. More particularly, the invention is directed for use in electric ranges with electrical heating elements. The invention has utility in applications such as newly manufactured ranges, or can be installed as a replacement for old burners in a previously installed electric range.
The placing of moveable electric elements in electric ranges is known in the prior art. Retractable burners for electric range systems are shown in U.S. Pat. No. 5,084,608, issued to Logan on Jan. 28, 1992; and U.S. Pat. No. 5,136,142, issued to Logan on Aug. 4, 1992. Each of these patents is briefly outlined in the following discussion, and is hereby incorporated by reference.
U.S. Pat. No. 5,084,608, issued to Logan on Jan. 28, 1992 discloses a "Retractable Burner For An Electric Range". This system discloses a method for raising and lowering an electric range burner element independently of the item being heated. The cookware rests on top of a plurality of support posts instead of resting directly on the electric burner element. The supporting posts and the cookware are fixed to the range surface and stay at a fixed level while the burner element can be raised and lowered with respect to the top of the support posts. A control knob raises and lowers the burner element in a parallel relationship to the bottom surface of the cookware. In this manner, traditional direct heating can be obtained when the element is raised against the bottom of the cookware, or a radiant gentle heat may be obtained by lowering the burner element away from the bottom of the cookware. This also allows for an on-stove cooling method by leaving the cookware on the burner surface while lowering the burner element from the cookware.
U.S. Pat. No. 5,136,142, issued to Logan on Aug. 4, 1992 discloses a "Retractable Burner For An Electric Range Having A Removable Burner Element". This specification discloses an improvement upon U.S. Pat. No. 5,084,608 by using a pivotal electrical connection to permit assembly and convenient unplugging and removal of the burner element. This allows for disassembly and cleaning of the apparatus of the invention and the reflective bowl connection to the range top.
The systems disclosed in these patents do not appear to allow for a front surface mounting of a control knob for raising and lowering the electric burner in relation to the cookware. In addition, these prior art systems do not appear to disclose a method for properly aligning and supporting a removable electric range element at the raised and lowered positions. Finally, these prior art systems do not disclose the use of a preset thermal switch for controlling the maximum temperature of the electrical burner element when in the lowered position. Hence, there is a need for an improved method for mounting a replaceable and retractable burner element for an electric range. In addition, there may be a need on some ranges for a thermal safety switch for a raised and lowered heating element for an electric heating element to protect the surrounding range components such as electrical wiring.